JP3788048B2 - Accumulated fuel injection system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure accumulation type fuel injection device applied to engines such as diesel engines and direct injection gasoline engines.
[0002]
[Prior art]
  Conventionally, as a fuel injection device for an engine, fuel stored in a common rail is supplied to a plurality of injectors, and a part of the fuel is used as a working fluid to operate the injectors. Type of common rail that injects fuel into the combustion chamber of the engine from the nozzle hole formed at the tip of the injectorAccumulation type calledThe fuel injection device or the working fluid is engine oil, the engine oil pressurized by the oil pump is accumulated in the high pressure oil manifold, the pressure increasing piston is operated by the high pressure oil supplied from the high pressure oil manifold to the injector through the control valve, 2. Description of the Related Art A pressure accumulation type fuel injection device such as an oil-actuated fuel injection device that boosts fuel introduced into a pressure increasing chamber by a pressure increasing piston and injects the fuel from an injector is known.
[0003]
FIG. 6 schematically shows an example of a common rail fuel injection device among the above-described accumulator fuel injection devices. The fuel sucked up by the feed pump 56 from the fuel tank 54 through the filter 55 and pressurized to a predetermined suction pressure is sent to the high-pressure fuel pump 58 through the fuel pipe 57. The high-pressure fuel pump 58 is a so-called plunger-type supply pump that is driven by an engine, for example. Supply. The fuel stored in the common rail 52 while being pressurized to a predetermined pressure is supplied from the common rail 52 to the plurality of injectors 51 through the fuel supply pipes 53. The illustrated engine is a six-cylinder engine, and injectors 51 for injecting fuel into respective combustion chambers are arranged in six cylinders (not shown). Obviously, the engine is not limited to the six cylinders shown, but may be four cylinders.
[0004]
The fuel relieved from the high-pressure fuel pump 58 is returned to the fuel tank 54 through the return pipe 60. Of the fuel supplied from the fuel pipe 59 to the injector 51, the fuel that has not been spent for injection into the combustion chamber is returned to the fuel tank 54 through the return pipe 61. The controller 62 includes various sensors, that is, a crank angle sensor that detects the engine speed, an accelerator opening sensor that detects an accelerator opening that represents the engine load, and a fuel temperature sensor that detects the temperature of the high-pressure fuel. Signals from various sensors such as are input. Other sensors that detect the operating state of the engine include an intake pipe pressure sensor that detects the intake pipe pressure, and a water temperature sensor that detects the coolant temperature. Further, a detection signal of the fuel pressure in the common rail 52 (hereinafter referred to as common rail pressure) detected by the pressure sensor 63 provided on the common rail 52 is sent to the controller 62.
[0005]
Based on these signals, the controller 62, for example, injects fuel into the corresponding combustion chamber with the optimal fuel injection amount at the optimal injection timing so that the engine output becomes optimal in accordance with the operating state. Thus, the injection conditions including the fuel injection timing and the injection amount are determined, and the fuel injection is controlled according to the injection conditions. The injection pressure of the fuel injected from the injector 51 is substantially equal to the common rail pressure. The fuel injection amount is determined by the injection period and the injection pressure, and the injection pressure is controlled by the amount of high-pressure fuel delivered to the common rail 52 controlled by the flow control valve 64. When the fuel in the common rail 52 is consumed by the fuel injection from the injector 51, or when the fuel injection amount is changed, the controller 62 controls the flow control valve 64 so that the common rail pressure becomes a predetermined pressure. The amount of fuel delivered from the high-pressure fuel pump 58 to the common rail 52 is controlled. When the engine operating state is the common rail internal pressure reduction request state, in order to quickly shift the common rail internal pressure to the desired reduced pressure, the high-pressure pressure regulator is electromagnetically opened to reduce the common rail internal pressure. Japanese Patent Laid-Open No. 10-54318 discloses a configuration in which a part of high-pressure fuel is forcibly opened to the low-pressure side.
[0006]
  In the conventional common rail type fuel injection device, in order to lower the common rail pressure, fuel is consumed by injection of fuel from the injector 51 into the combustion chamber or dynamic leakage from the pressure control chamber, or static leakage from the injector. Consumes fuel byBecauseThere is no means outside. In a transition state where the fuel injection conditions change abruptly, the target common rail pressure is not sufficiently trackable, and the common rail pressure does not decrease completely, or even if it decreases, it takes too much time. To do. Therefore, as shown in the common rail pressure graph shown in FIG. 5A, the pressure deviation graph shown in FIG. 5B, and the NOx generation rate graph shown in FIG. There is a problem of doing. That is, when the drop of the common rail pressure shown in (a) is delayed as shown in C, a pressure adjustment delay E appears as shown in the pressure deviation graph (b). Therefore, the fuel injection pressure is high, and in the graph (c) of the NOx generation rate, the time domainIAs shown in graph H, the NOx generation rate is high. Graph (d) is a graph showing the smoke discharge amount.
[0007]
Therefore, in FIG. 6, it has been proposed to connect the common rail 52 and the return pipe 61 by a leak path 66 and to arrange a pressure relief valve 67 in the leak path 66. The pressure relief valve 67 is composed of, for example, an electromagnetic valve having a solenoid 68 as shown in FIG. The high-pressure fluid inflow passage 69 communicates with the inflow passage 71 of the inflow side piece 70. The high-pressure fluid released by the pressure relief valve 67 is released through the outflow path 74 of the outflow side member 73. A valve body 76 is provided at the tip of the armature 75. The armature 75 is urged by a spring 77 so that the valve body 76 closes the outlet side opening 72 of the inflow passage 71 of the inflow side piece 70 with a constant force. When the armature 75 is attracted against the force of the spring 77 by the excitation of the solenoid 68, the valve body 76 opens the outlet side opening 72 of the inflow passage 71, and the pressure of the high-pressure fluid in the common rail 52 can be released. .
[0008]
[Problems to be solved by the invention]
In such a structure of the pressure relief valve 67, when the common rail pressure is increased to, for example, 200 MPa or more, the amount of static leakage increases even when the pressure relief valve 67 is not in operation. The common rail pressure does not increase. Therefore, there is a problem to be solved in that the static leakage from the pressure relief valve is eliminated while maintaining the sealing characteristics even when the common rail pressure becomes high.
[0009]
[Means for Solving the Problems]
An object of the present invention is to solve the above-mentioned problem. A pressure relief valve for releasing the common rail pressure is provided to ensure a rapid decrease in the common rail pressure, and the pressure relief valve when the common rail pressure becomes high is provided. An object of the present invention is to provide an accumulator type fuel injection device capable of dealing with a high common rail pressure required for improving engine performance and exhaust gas characteristics by eliminating static leakage.
[0010]
  The present invention detects an operating state of an engine for accumulating a working fluid sent from a pump, an injector that operates based on a pressure action of the working fluid supplied from the accumulating chamber, and injects fuel into a combustion chamber. A pressure accumulating fuel injection device comprising: a detecting means; a controller for controlling fuel injection from the injector in response to a detection signal from the detecting means; and a pressure relief valve for releasing the working fluid pressure in the pressure accumulating chamber, The controller outputs a pressure reducing command signal for reducing the pressure of the working fluid in the pressure accumulating chamber based on the detection signal, and the pressure relief valve is an operation stored in the pressure accumulating chamber in a closed state. The self-seal structure is energized in the valve closing direction by the pressure action of the fluid, and operates in response to the pressure reducing command signal. In the pressure accumulation type fuel injection device that opens the valve by an actuator and depressurizes the working fluid pressure in the pressure accumulation chamber, the pressure relief valve passes through a throat portion provided in a discharge path for discharging fuel in the pressure accumulation chamber. A valve stem portion extending to the pressure accumulating chamber side of the discharge passage, and a valve seat provided integrally with the tip of the valve stem portion and formed in the inlet side opening of the throat portion in a closed state A valve member comprising a valve body portion having a valve face that is in contact with each other, and a concave portion for pressure cancellation is formed on either the valve seat or the valve face, An annular groove formed in the valve face and a radial groove that extends radially from the annular groove and communicates with a discharge passage that discharges fuel in the pressure accumulating chamber.At the same time, the valve member is fixed to the end of the valve stem by a reinforcing plate by laser welding.The present invention relates to a pressure accumulation type fuel injection device.
[0011]
In the accumulator fuel injection device according to the present invention, when the pressure of the working fluid in the accumulator is to be reduced, for example, when the operation is suddenly shifted from the high load operation to the low load operation, Based on the detection signal from the detection means for detecting the controller, the controller outputs a pressure reduction command signal for reducing the pressure of the working fluid in the pressure accumulating chamber. The pressure relief valve is opened by an actuator that operates based on the depressurization command signal to release the working fluid pressure in the accumulator and depressurize the fuel pressure in the accumulator. When the pressure in the accumulator is increased as in high load operation, the relief valve is closed. The relief valve has a self-sealing structure that is urged in the valve closing direction by the pressure action of the working fluid stored in the pressure accumulating chamber when the valve is closed, so that static leakage from the pressure accumulating chamber is reliably prevented. The
[0012]
The pressure relief valve is integrated with a valve stem portion that extends through a throat portion provided in a discharge passage for discharging fuel in the pressure accumulation chamber to the pressure accumulation chamber side of the discharge passage, and a tip of the valve stem portion. And a valve member comprising a valve body portion having a valve face that comes into contact with a valve seat formed in the inlet side opening of the throat portion when the valve is closed. Since the valve stem portion and the valve body portion were initially formed as separate bodies, it is possible to obtain a small-diameter and high-precision one. The combined valve member reduces the area of the portion that receives the fuel pressure. Therefore, the valve opening operating force when pushing the valve member at the time of valve opening becomes small.
  In addition, a pressure canceling recess is formed on either the valve seat or the valve face. The recess for pressure cancellation is a recess into which the pressure in the common rail is introduced. By forming the concave portion, the fuel pressure introduced into the concave portion acts so as to cancel the pressing force from the pressure receiving surface, so that the valve opening operating force when pushing out the valve member at the time of valve opening becomes small.
  The concave portion includes an annular groove formed in the valve seat or the valve face, and a radial groove that extends radially from the annular groove and communicates with a discharge passage that discharges fuel in the pressure accumulating chamber. When the recess is formed in the valve face of the valve body, the recess communicates with an annular groove formed in the valve face and a discharge passage that extends radially from the annular groove and discharges fuel in the pressure accumulating chamber. And radial grooves. The concave portion does not necessarily have a groove shape, but if the groove has such a shape, the seat of the valve body portion with respect to the valve seat is stabilized, and uneven wear of the valve seat or the like can be prevented.
  Further, the valve member is fixed to the end of the valve stem portion by a reinforcing plate by laser welding. The valve body part has a center hole, the tip of the valve stem part is fitted into the center hole, and a reinforcing plate is applied to the tip surface of the valve stem part and the opposite end face of the valve seat in the valve body part, It is preferable to integrate the valve stem portion, the valve main body and the reinforcing plate by laser welding. The reinforcing plate prevents cracks from occurring in the valve body and the valve stem.
[0016]
The pressure accumulation fuel injection device is a common rail fuel injection device in which the working fluid is fuel sent from a high pressure fuel pump as the pump, and the pressure accumulation chamber is a common rail for storing fuel.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing an embodiment of a pressure relief valve used in an accumulator fuel injection apparatus according to the present invention, FIG. 2 is an enlarged cross-sectional view of the main part of the pressure relief valve shown in FIG. 1, and FIG. 4 is a plan view showing the valve body, FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3, and FIG. In FIG. 4, the structure around the valve body is indicated by an imaginary line. Since the pressure accumulation type fuel injection device according to the present invention can use the one shown in FIG. 6 as the overall configuration, the description thereof will be omitted except for the structure of the pressure relief valve.
[0018]
  Referring to FIG. 1, a pressure relief valve 1 used in this accumulator type fuel injection device includes a male screw portion 3 formed at one end of a main body 2 and a base of a common rail 52.42The taper portion 4 formed at the tip of the male screw portion 3 is brought into liquid-tight contact with the taper hole portion 44 formed at the back of the screw hole portion 43. Thus, the common rail 52 is attached in a sealed state. A discharge passage 5 for discharging high-pressure fuel is formed in the main body 2 of the pressure relief valve 1, and the discharge passage 5 is connected to a high-pressure fuel reservoir chamber 45 formed in the common rail 52.
[0019]
A hollow hole 6 is formed in the main body 2 along the axis. The hollow hole 6 is provided with a control block 7 in which a main valve structure of the pressure relief valve 1 for opening and closing a discharge passage 5 to be described later is formed, and a pressing block 8 for pressing the control block 7. The actuator for operating the pressure relief valve 1 is an electromagnetic actuator 9 composed of an electromagnetic solenoid 10, which is attached to a fixed cap 11 by a solenoid block 12, and the fixed cap 11 is screwed into the outer periphery of the main body 2. Thus, the control block 7 and the pressing block 8 are attached in the main body 2 while being pressed into the hollow hole 6 by the solenoid block 12. The electromagnetic solenoid 10 operates in the left direction in FIG. 1 in response to a control signal from the controller 62, and drives the pressure relief valve 1 in the opening direction.
[0020]
The movement of the plunger 13 of the electromagnetic solenoid 10 is transmitted to the control member 14. The control member 14 is urged in a return direction by a return spring 15 interposed between the control block 14 and when the electromagnetic solenoid 10 is demagnetized, the control member 14 is returned to a non-operating position. , The pressure relief valve 1 is closed. When the electromagnetic solenoid 10 is energized, the control member 14 is moved to the operating position against the urging force of the return spring 15 to shift the pressure relief valve 1 to the open state. The control member 14 can repeat the reciprocating motion in the axial direction at a high speed by the operation of the electromagnetic solenoid 10. A discharge passage member 16 is attached to the outer periphery of the main body 2 by a fixing cap 11 in a sandwiched state. The discharge passage member 16 is formed with a discharge passage 17 that can communicate with the discharge passage 5 on the common rail 52 side through the pressure relief valve 1.
[0021]
FIG. 2 is an enlarged view showing details of the control block 7, the control member 14, and the valve member 25 of the pressure relief valve 1. The control block 7 is formed with a small-diameter valve inlet 20 that communicates with the discharge path 5 on the common rail 52 side on one side, and a large-diameter spring housing that houses one end of the return spring 15 on the other side. A small-diameter valve outlet 23 in which the head portion 27 of the valve stem 26 of the pressure relief valve 1 to be described later, and a medium-diameter control member guide portion 22 that slidably guides one end portion of the portion 21, the control member 14. Is formed. The valve inlet portion 20 and the valve outlet portion 23 are communicated with each other by a throat portion 24 having a minimum diameter.
[0022]
The valve structure portion of the pressure relief valve 1 includes a valve stem 26 having a head portion 27 that comes into contact with the control member 14 and a valve body 28 coupled to the end of the valve stem 26 by laser welding. The valve stem 26 constitutes the valve stem portion of the present invention, and the valve body 28 constitutes the valve body portion of the present invention. Since the return spring 15 accommodated in the spring accommodating portion 21 is interposed in a compressed state, it always applies a force for urging the control member 14 in a direction away from the valve stem 26. That is, the return spring 15 urges the pressure relief valve 1 in the valve closing direction. A discharge passage 18 extending in the radial direction is formed so as to open to the control member guide portion 22, and the discharge passage 18 is connected to the discharge passage 17 through a discharge passage 19 formed in the main body 2 in the radial direction. ing. The discharge paths 5, 17, 18, 19 and the throat section 24 constitute a leak path 38.
[0023]
The valve stem 26 is inserted through the throat hole 24 formed in the control member 14 leaving a slight gap and extends into the valve inlet 20. A valve body 28 that can be opened by shutting off the communication between the valve inlet 20 and the throat 24 is provided at the end of the valve stem 26. As shown in FIGS. 3 and 4, a central hole 29 is formed in the valve body 28, and a step portion 30 having a tapered surface is formed in the middle of the central hole 29. The valve stem 26 and the valve body 28 are manufactured separately. When the valve stem 26 and the center hole 29 of the valve body 28 are fitted, the stepped portion 30 and the narrow diameter portion of the valve stem 26 are engaged and positioned, and the lower end face 31 of the valve body 28 and the lower end face of the valve stem 26 are positioned. 32 (shown by an imaginary line in FIG. 4). The valve member 25 is integrated by laser welding with a reinforcing plate 33 applied to the lower end surface 31 of the valve body 28 and the lower end surface 32 of the valve stem 26 disposed through the valve body 28. The reinforcing plate 33 functions to prevent cracks from occurring in the valve body 28 and the valve stem 26 exposed to high pressure. Moreover, since the valve stem 26 and the valve body 28 are manufactured separately, the diameters of the valve stem 26 and the valve body 28 can be reduced. Accordingly, since the valve member 25 itself is downsized, the fuel pressure acting on the valve member 25 is small.
[0024]
The valve body 28 has a valve face 39 that is a conical tapered surface at the upper end of the cylindrical portion 36. The valve face 39 has a shape that fits exactly with a valve seat 40 having a conical concave surface formed in the opening of the throat portion 24 on the valve inlet portion 20 side. Therefore, when the electromagnetic solenoid 10 is demagnetized and the control member 14 is biased to the return position by the return spring 15, the valve element 28 is biased in the valve closing direction by the high fuel pressure of the common rail 52. That is, the pressure relief valve 1 has a self-sealing structure that is urged in the valve closing direction by the pressure action of the high-pressure fuel stored in the common rail 52 in the valve-closed state. As shown in FIGS. 3 and 4, the valve face 39 is formed with an annular groove 34 concentrically with the center hole 29. Radial grooves 35 are formed radially outward from the annular groove 34 at an equal angle. ing. That is, the radial grooves 35 are formed to be point symmetric. The radial groove 35 allows the annular groove 34 and the valve inlet portion 20 to communicate with each other, and the fuel pressure in the valve inlet portion 20, that is, in the common rail 52, can be guided to the annular groove 34. The fuel pressure introduced into the annular groove 34 acts as a force for pushing down the valve body 28 against the valve body 28 and acts so as to cancel the force pushing the valve body 28 against the valve seat 40. Accordingly, the force for pushing down the valve element 28 when the valve is opened is small, and even a small actuator can sufficiently function.
[0025]
When the electromagnetic solenoid 10 is not energized, that is, not driven, the valve member 25 is closed by the spring force applied by the return spring 15. In this state, the valve face 39 of the valve body 28 is in surface contact with the valve seat 40. The leak path 38 is closed by sitting in the state. When the electromagnetic solenoid 10 is excited, the valve stem 26 of the valve member 25 overcomes the spring force of the return spring 15 and is pushed leftward in FIGS. At this time, the valve face 39 of the valve body 28 is separated from the valve seat 40 and opens the opening on the valve inlet 20 side of the leak path 38, so that fuel flows and the fuel pressure in the common rail 52 is reduced between the throat 24 and the valve. It passes through the gap with the stem 26 and is released to the discharge path 17 through the discharge paths 18 and 19.
[0026]
  This embodiment is configured as described above and operates as follows. When electromagnetic solenoid 10 is not excitedReturnThe spring 15 urges the control member 14 to the right in the drawing. Since the high fuel pressure on the common rail 52 side acting on the valve inlet 20 acts on the valve body 28 to press the valve face 39 against the valve seat 40, the valve member 25 has the fuel pressure on the common rail 52. The leak path 38 is closed in a self-sealing state in which the sealing force increases as the height increases. In this state, high-pressure fuel from the common rail 52 cannot flow from the valve inlet portion 20 to the throat portion 24, and static leak of the common rail 52 can be prevented. Therefore, even when there is a request for increasing the pressure of the common rail 52 according to the operating state of the engine, the pressure of the common rail 52 can be rapidly increased.
  When a pressure reduction request is made to the common rail pressure according to the operating state of the engine, the controller 62 excites the electromagnetic solenoid 10,As shown in Figure 2The control member 14Until contact with the left end of the control member guide 22It is pushed to the left in FIG. 2 against the return spring 15. The control member 14 pushes the valve stem 26 of the valve member 25 to the left against the valve closing force based on the fuel pressure at the valve inlet 20, and causes the valve face 39 of the valve body 28 to be detached from the valve seat 40. Accordingly, the pressure relief valve 1 is opened, and the high-pressure fuel in the common rail 52 is discharged from the valve inlet portion 20 to the outside of the pressure relief valve 1 through the valve throat portion 24, the valve outlet portion 23, and the discharge passages 18, 19. The common rail pressure is rapidly reduced.
[0027]
  FIG. 5A shows the time change of the common rail pressure, FIG. 5B shows the time change of the deviation from the target common rail pressure, FIG. 5C shows the time change of the NOx generation rate in the exhaust gas, and the same ( d) represents the amount of smoke discharged. According to the present invention, since the pressure relief valve 1 is provided, the pressure relief valve 1 is provided as shown by B in FIG. 5A when the engine operating state is the common rail pressure reduction request state. Compared to the case indicated by C, the delay in the decrease in common rail pressure is prevented.StopIn addition, the fluctuation of the common rail pressure can be reduced. Further, when viewed from the deviation from the target common rail pressure shown in (b), according to the present invention in which the pressure relief valve 1 is provided, there is no significant change in the pressure deviation as indicated by D, but the pressure relief. If the valve 1 is not provided, pressure fluctuations occur as indicated by E and F. In addition, as shown by the occurrence rate of NOx in (c), when the pressure relief valve 1 is provided in the range of the time interval I (indicated by G), the pressure relief valve 1 is provided. Compared to the absence (indicated by H), NOx generation can be reduced by about 17%.
[0028]
Further, according to this accumulator fuel injection device, the annular groove 34 is formed concentrically with the center hole 29 in the valve face 39, and the radial groove 55 is formed radially outward from the annular groove 34. Therefore, the fuel pressure in the valve inlet 20 can be guided to the annular groove 34, and the valve body 28 receives the force in the valve opening direction by the fuel pressure introduced into the annular groove 34, so that it is smaller than the conventional one. The pressure relief valve 1 can be opened by force. Accordingly, not only the small electromagnetic solenoid 10 can be adopted, but also the power consumed by the electromagnetic solenoid 10 can be reduced.
[0029]
In the above-described embodiment, an example in which the valve stem 26 and the valve body 28 of the valve member 25 are integrated by laser welding via the reinforcing plate 33 has been described. Can be integrated into the valve body 28 by press-fitting the tip of the valve stem 26. In the above embodiment, the electromagnetic solenoid 10 is described as an example of the valve opening actuator 9. However, other means such as a piezoelectric element may be used.
[0030]
As described above, this pressure accumulation type fuel injection device has been described as a common rail type fuel injection device. However, an oil operation type in which the working fluid is oil fed from a high pressure oil pump as a pump and the pressure accumulation portion is a high pressure oil manifold for storing oil. Obviously, the present invention may be applied to a fuel injection device.
[0031]
【The invention's effect】
Since the pressure accumulation type fuel injection device according to the present invention is configured as described above, the higher the fuel pressure in the common rail, the stronger the fuel pressure is used as the closing force for closing the pressure relief valve. , Fuel leakage through the pressure relief valve can be avoided, the useless work burden on the high-pressure fuel pump can be avoided, and the common rail pressure can be increased early. Further, since the contact of the valve face with the valve seat is a surface contact, the surface pressure can be set to an appropriate value, and wear of the valve seat can be avoided. If the pressure relief valve is a poppet valve and the valve seat is composed of a tapered concave surface that abuts the valve body of the poppet valve, the pressure relief valve is stable by fitting the tapered surfaces even when turbulent fuel flow occurs. In addition, the valve can be operated quickly, and when the valve is closed, a sufficient seal can be obtained between the valve face and the valve seat to prevent fuel leakage.
[0032]
In addition, since the valve stem portion and the valve body portion are molded separately, a thin and accurate valve stem portion and valve body portion can be obtained. In the valve member manufactured by combining the two, the area of the portion that receives the fuel pressure is reduced. Therefore, since the opening force of the pressure relief valve can be small when the valve is opened, a small actuator can be used and power consumption can be reduced.
[0033]
  Also, a recess for introducing fuel pressure into the valve bodyButFormationBecauseThe fuel pressure introduced into the recess acts to cancel the force in the direction of closing the pressure relief valveIt will beThere is an advantage that the valve opening operation force can be further reduced. In addition, the concave portion extends radially outward from the annular groove formed in the valve face.Exhaust path for discharging fuel in the accumulator chamberConsists of radial grooves communicating withBecauseThere is an advantage that the seat of the valve body portion with respect to the valve seat is stable, and uneven wear of the valve seat or the like can be prevented. Further, when the valve stem portion and the valve body portion are integrated, if the valve stem portion and the valve body portion are integrated by laser welding via the reinforcing plate, the valve body portion and the valve stem portion are integrated by the reinforcing plate. There is an advantage that cracks can be prevented from occurring.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a pressure relief valve used in an accumulator fuel injection device according to the present invention.
FIG. 2 is an enlarged cross-sectional view of the main part of the pressure relief valve shown in FIG.
3 is a plan view showing a valve body portion of the pressure relief valve shown in FIG. 1. FIG.
4 is a cross-sectional view taken along a plane indicated by line AA in FIG.
FIG. 5 is a graph illustrating an operating state of the pressure accumulation type fuel injection device according to the present invention.
FIG. 6 is a schematic view showing a conventional accumulator fuel injection device.
FIG. 7 is a cross-sectional view of a pressure relief valve used in a conventional accumulator fuel injection device.
[Explanation of symbols]
1 Pressure relief valve
2 body
5 discharge channel
7 Control block
9 Actuator
10 Electromagnetic solenoid
13 Plunger
14 Control members
15 Return spring
20 Valve inlet
23 Valve outlet
24 Throat
25 Valve member
26 Valve stem
28 Disc
29 Center hole
31 Lower end surface
32 Lower end surface
33 Reinforcement plate
34 Annular groove (concave)
35 Radial groove (recess)
38 Leak Road
39 Valve face
40 Valve seat
51 Injector
52 common rail
58 High pressure fuel pump
62 Controller
63 Pressure sensor
66 Leak Road

Claims (2)

A pressure accumulating chamber for accumulating working fluid delivered from a pump; an injector that operates based on a pressure action of the working fluid supplied from the pressure accumulating chamber to inject fuel into the combustion chamber; A pressure-accumulation fuel injection apparatus comprising a controller for controlling fuel injection from the injector in response to a detection signal from a detection means, and a pressure relief valve for releasing the working fluid pressure in the pressure-accumulation chamber, wherein the controller A pressure reducing command signal for reducing the pressure of the working fluid in the pressure accumulating chamber is output based on a detection signal, and the pressure relief valve has a pressure action of the working fluid stored in the pressure accumulating chamber in a closed state. The actuator is configured in a self-sealing structure that is urged in the valve closing direction by the actuator, and operates in response to the pressure reducing command signal. In an accumulator fuel injection system is intended for reducing the operating fluid pressure in the accumulator chamber opened by motor,
The pressure relief valve is integrated with a valve stem portion that extends through a throat portion provided in a discharge path for discharging the working fluid in the pressure accumulation chamber to the pressure accumulation chamber side of the discharge path, and a tip of the valve stem portion. And a valve member comprising a valve body portion having a valve face that comes into contact with a valve seat formed at an inlet side opening of the throat portion in a closed state, and the valve seat or the valve A concave part for pressure cancellation is formed in one of the faces, and the concave part extends radially from the annular groove formed in the valve seat or the valve face and allows the working fluid in the pressure accumulating chamber to flow. together it is composed of a radial groove communicating with the discharge passage for discharging, the valve member, especially that it is fixed by laser welding the valve body portion at an end portion of the valve stem by the reinforcing plate Accumulator fuel injection apparatus according to. The pressure accumulation fuel injection device is a common rail fuel injection device in which the working fluid is fuel sent from a high pressure fuel pump as the pump, and the pressure accumulation portion is a common rail for storing fuel. The pressure accumulation type fuel injection device according to 1.

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